Ian Chetter
Senior Lecturer in Vascular Surgery,
Academic Vascular Unit, Hull Royal Infirmary, Hull, UK

In summary, the case is a 78-year-old woman with a 5.5 cm abdominal aortic aneurysm (AAA). She has stable hypertension controlled with ‘triple’ therapy and stented left renal artery stenosis (RAS), and residual ‘tight’ right RAS following failed stenting. She has moderate chronic, but apparently stable, renal failure (post stent serum creatinine 243-300 µmol/l.)

Current Problems

What to do about the AAA?

Analysis of the case

Level 1 evidence clearly demonstrates that an asymptomatic AAA of less than 5.5 cm in diameter should be managed expectantly with surveillance [1,2]. The risk of rupture is proportional to diameter and the annual rupture rate of a 5.5 cm AAA would be in the order of 5-10%[3]. Elective AAA repair is associated with a perioperative mortality of approximately 3-10%[4]. This specific patient would appear to be very anxious regarding her AAA and ‘keen on intervention’. On balance, therefore, the AAA should be repaired. She would require preoperative anaesthetic and cardiac assessment.

Endovascular or open AAA repair?

Endovascular aortic aneurysm repair (EVAR) is a topic for debate. Technical success rates are high once the initial learning curve is conquered. Total hospital stay is reduced, pain and early quality of life scores are improved when compared to open surgical repair. However, reintervention rates following EVAR are approximately 20% in the first 12 months and 10% per annum thereafter [5,6]. Lifelong graft surveillance (which may cause further anxiety) is necessary following EVAR, and the long-term durability of these devices is unproven. Open repair, however, is a durable procedure with excellent long-term results [3]. A multicentre randomised trial comparing EVAR and open AAA repair has been recruiting patients since September 1999[8]. If this patient consented to EVAR she could be entered into this study. If the patient declined EVAR, open repair would be justified.

What to do about the right RAS?

This patient now has essentially unilateral RAS following successful stenting of the left RAS. It is not particularly clear in the case report whether stenting of the right renal artery was actually attempted.

Preoperative management.A potentially relative indication for further intervention on the right renal artery is the preservation and prevention of renal function deterioration. This, however, is not supported by current best medical evidence; therefore, preoperative revascularisation of the right renal artery is not indicated[7].

Peroperative management.The other concern is that during AAA repair the renal artery or arteries may occlude. Thus, given the failed original right renal stent, it would need to be ascertained prior to AAA repair whether endovascular revascularisation of the right renal artery is feasible. If not feasible, this could be considered to be a relative contraindication to endovascular AAA repair. At open repair, the aortic cross clamp could be placed above the renal arteries, below the superior mesenteric artery, thus the renal orifices could be identified and the kidneys perfused with cooled renal preservation solution while the superior anastomosis was performed just below the renal artery ostia. The other option would be to place the aortic cross clamp just below the renal arteries and monitor renal blood flow with intraoperative continuous wave Doppler or duplex scanning. If infrarenal clamping resulted in renal artery occlusion/low flow or distal emboli were detected, a supra renal clamp could then be placed. If surgical revascularisation was indicated (e.g.renal artery damage) the operation of choice on the right would be a saphenous vein interposition graft between the side of the hepatic artery and the distal end of the transected right renal artery. On the left, a splenorenal bypass, during which the transected splenic artery is anastomosed end-to-end to the transected left renal artery, is probably the preferred option.

Postoperative management.Treatment of the right RAS (endovascular if possible) would only be indicated if this lady develops an appropriate indication (e.g. flash pulmonary oedema or deteriorating renal function).

Conclusion

The AAA should be repaired. If endovascular repair is requested then the patient should be entered into the EVAR I study; if not, then open repair should be used. Management of the right RAS should be as follows:
1. Preoperative: no indication for intervention.
2. Preoperative: (a) open repair-suprarenal clamp to prevent renal artery occlusion or infrarenal clamp with interoperative monitoring. If renal artery occlusion/damage did occur, surgical revascularisation is indicated. (b) EVAR-should renal artery occlusion occur, endovascular revascularisation may still be possible.
3. Postoperative: revascularisation (endovascular if possible) only recommended if appropriate indications develop.

References

1. UK Small Aneurysm Trial Participants. Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms.. Lancet 1998; 352: 1649-55.

2. Lederle, FA,Wilson, SE, Johnson, GR et al. Aneurysm Detection and Management Veterans Affairs Cooperative Study Group.Immediate repair compared with surveillance of small abdominal aortic aneurysms. . N Engl J Med 2002; 346: 1437-44.

3. Cronenwett, JL, Krupski, WC, Rutherford, RB. Abdominal and aortic aneurysms. In: Rutherford’s Vascular Surgery. 5th edn, (Eds J L Cronenwett, P Gloviczki, K W Jonston, R F Kempczinski and W C Krupski). Philadelphia, WB Saunders, 2000: 1246-80.

4. Bayly, PJ, Matthews, JN, Dobson, PM, Price, ML, Thomas, DG. In-hospital mortality from abdominal aortic surgery in Great Britain and Ireland:Vascular Anaesthesia Society Audit..Br J Surg 2001; 88: 687-92.

5. Walschot, LH, Laheij, RJ, Verbeek, AL.Outcome after endovascular abdominal aortic aneurysm repair: a meta-analysis.. J Endovasc Ther 2002; 9: 82-9.

6. Adriaensen, ME, Bosch, JL, Halpern, EF, Myriam Hunink, MG, Gazelle, GS. Elective endovascular versus open surgical repair of abdominal aortic aneurysms: systematic review of short term results.. Radiology 2002; 224: 739-47.

7. van Jaarsveld, BC, Krijnen, P, Pieterman, H et al. The effect of balloon angioplasty on hypertension in atherosclerotic renal-artery stenosis. Dutch Renal Artery Stenosis Intervention. Cooperative Study Group. N Engl J Med 2000; 342:1007-14.

8. Powell, JT, Greenhalgh, RM. Clinical practice. Small abdominal aortic aneurysms.. N Eng J Med 2003; 348: 1895-901.

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